1. Technical Field
The invention disclosed herein relates generally to electrical terminal applicators, and more particularly to providing terminal applicator methods for automatically crimping terminals or connectors to wires wherein the terminals or connectors are provided in strip form and may be of varying sizes, shapes, and pitches.
2. Background Art
As is known in the art, a wide range of electronic and electrical products use crimp terminals to make electrical connections from wires to other wires, printed circuit boards or other components. Generally, a crimp terminal consists of three sections that function to create a proper electrical connection. The first section is the contact area, which is designed to physically connect with a mating terminal to establish an electrical connection. For example, a “pin” terminal would slide inside of a “socket” terminal to make the connection. The second section is the wire crimp area, which is designed to capture the end of a wire. The wire in this area of the terminal must be stripped; that is, the insulation around the conductor of the wire must be removed to expose the conductor portion. Metal tabs on the terminal are folded around the stripped wire very tightly. Generally, the tabs are folded so tightly that a “cold” weld occurs between the wire strands and the terminal. This crimping action provides a physical connection of the terminal to the wire as well as an electrical connection. The electrical connection is highly resistant to moisture, temperature changes, corrosion, and other negative environmental conditions that may be present. The third section is the strain relief area, which is designed to capture the wire where the insulation begins. Generally, in this section metal tabs are loosely folded around the wire insulation. The strain relief area prevents flexure of the wire from breaking wire strands in the wire crimp area.
Generally, the process for attaching a crimp terminal to a wire involves several basic steps. First, the end of the wire must be stripped to expose the correct length of bare conducting wire. Second, the stripped wire must be positioned over the terminal to properly orient the wire with the terminal. Finally, the tabs on the wire crimp and strain relief areas of the terminal must be folded and compressed, or crimped, on to the wire in a defined manner in order to create and maintain a proper electrical connection.
To accomplish the last step described above relating to crimping the terminal onto the wire, tooling specifically designed for the terminal must be used. In some cases, hand tools are used with terminals that are packaged as loose pieces. In this case, an operator secures the terminal in the hand tool by placing the base of the terminal on an anvil. While using one hand to maintain the prepared wire end in the correct position over the terminal, the operator uses the other hand to close the handles of the tool. A set of precisely designed blades then closes against the terminal. The action of the blades against the terminal as the terminal sets in the anvil provides the correct folding of the tabs in the wire crimp and strain relief sections. The use of hand tools and loose-piece terminals is a very common and popular method to crimp terminals to wires, especially amongst homeowners and electrical contractors. However, given the labor intensity and time consuming nature of this manual process, the use of hand tools is not suitable for medium to high speed/volume production.
To support high volume production, terminal applicators have been used wherein applicator tooling is typically used in conjunction with a press. The applicator is installed in the press and generally a unique applicator is required for each terminal or family of terminals (i.e., terminals of similar size, shape, etc.). In these terminal applicators, terminals packaged in daisy-chain fashion on a carrier strip (as opposed to loose-piece) are fed from a reel into a guide integral to the applicator. The applicator contains a fixed anvil, shear block, and moveable blades, all suitable for crimping the wire crimp and strain relief portion of the terminal and cutting the terminal from its carrier strip. The press has means for holding the base of the applicator in a fixed position in the press and also has means for lowering/raising a ram in the applicator to which the blades are attached. If the press is mounted on a bench-top, an operator places a prepared wire in the proper position over the terminal and actuates a pedal. The pedal triggers the press to lower the ram and then raise it to its starting position, all in one rapid and complete motion.
In these typical press terminal applicators, movement of the ram by the press results in the following actions, all occurring within the applicator. First, given that the blades are attached to the ram, as the ram is lowered, the blades are pressed against the terminal as it rests against the fixed anvil. This action crimps the terminal to the wire. Second, the shear block is activated to cut the terminal from the terminal carrier strip. Finally, through a cam mechanism in the applicator, movement of the ram also drives a feed pawl which advances terminals into position over the anvil. Depending upon the design of the applicator and specific requirements of the terminal, terminals may be advanced on either the upward or downward motion of the ram (known as post-feed or pre-feed). Additionally, in some applicators, the terminal is advanced using a pneumatic feed mechanism mounted on the applicator.
In addition to being mounted on bench-tops as described hereinabove, terminal applicator presses can also be installed on fully automated wire processing equipment as shown in the prior art. In this configuration, the press is activated under control of the wire processing equipment as opposed to manual control. Once set-up and operational, this type of equipment cuts, strips, and terminates wires with no human involvement with production rates that can support high volume operations. In some fully automated wire processing equipment, the presses have a feature called crimp force analysis. In these presses, the force required to move the ram in the applicator is measured and analyzed to determine the quality of the crimp.
Various configurations of terminal applicators of varying types are known in the prior art as described hereinbelow.
U.S. Pat. No. 3,553,814 to Rider is directed to an applicator for crimping electrical terminals in the form of a continuous belt onto the ends of wires and substantially simultaneously removing the crimped terminations from the belt. The applicator has a crimping die and crimping anvil which are movable relatively towards and away from each other and the belt of terminals is fed along a feed path extending behind the dies to present the leading terminal on the belt to the dies. After crimping, the terminal feed means moves laterally off the feed path away from the dies while the terminal is held between the dies so that the crimped terminal is broken away from the belt. A pair of spaced-apart sprocket wheels are disclosed which engage spaced-apart perforations on the terminal belt and push/pull the belt through the crimping zone during operation.
U.S. Pat. No. 4,043,032 to Spangler is directed to a terminal applicator apparatus wherein terminals provided on a continuous belt are indexed towards crimping dies and wherein the crimped wire end is moved away from the belt and the crimping dies so that the terminal is broken away from the belt. A sprocket wheel is provided which includes teeth that engage perforations on the belt and function to index the belt through the press, thereby presenting the lead terminal of the belt at the crimping station during each operating cycle. An ejection means spaced laterally from the feed path moves into engagement with the wire and away from the crimping dies, while the other end of the wire is held by a wire clamp, so that the crimp terminal is broken away from and removed from the belt.
U.S. Pat. No. 4,667,397 to Day et al. discloses a machine for crimp connecting an electrical lead wire to a terminal wire or the like. The device includes means for cooperatively feeding a length of electrical lead, a length of terminal, and a crimp connector strip carrying a series of crimp connectors. The device further includes a die set assembly, a cutter movable with respect to the die set assembly, a crimper, means for positioning the cutter relative to the crimper, terminal wire length positioning means, and means for locking the means for positioning the cutter once the desired terminal length has been set.
U.S. Pat. Nos. 4,718,160 and 4,805,278 to Bulanda et al. are each directed to a terminal strip applicator that purports to disclose a self-adjusting mechanism that can accept a wide variety of structurally disparate continuously molded terminal strips and accurately apply each terminal to a wire without the need for readjustment and/or exchange of the working parts of the strip feed mechanism. The apparatus includes a terminal strip applicator feed track that automatically adjusts to accept terminal strips of varying widths and varying terminal contours. The apparatus further includes a terminal feeding mechanism for resiliently biasing the terminal strip for sequentially advancing a lead terminal of the terminal strip. The terminal feeding mechanism of these patent documents includes a feed link and a feed finger on the applicator itself for feeding of the terminal strip.
U.S. Pat. No. 5,131,124 to Skotek describes a strip feeding mechanism for terminal applicators for crimping terminals onto the ends of wires. The strip feeder is actuated by a rack on the applicator ram and a gear train which is between the applicator ram and the actual feeding mechanism. The strip feeding mechanism comprises a feed pawl or feed finger which is on the end of a pivotable arm and which moves the terminal strip.
U.S. Pat. No. 5,491,887 to Quinn is directed to an electrical terminal applicator with an improved split cycle system for the crimping die means of the applicator. The apparatus includes moving means mounted directly on the applicator frame adjacent the applicator ram and connected to the crimping die for moving the crimping die through a first portion of movement into engagement with an uncrimped terminal to preposition the terminal for crimping thereof. Additionally, the applicator ram thereafter can move the crimping die through a second portion of movement to effect crimping of the terminal.
U.S. Pat. No. 5,440,799 to Marshall et al. and U.S. Pat. No. 5,481,796 to Quinn are each directed to electrical terminal applicators with improved terminal tape moving means. Marshall et al. provides a terminal applicator having an applicator feeding system employing a very low-profile tooth mechanism wherein the mechanism is adjustable to vary the feed stroke thereof to accommodate terminal tapes with different pitches between the terminals. The applicator of Marshall et al. includes fixed stop teeth that engage the indexing apertures of a terminal tape to prevent the tape from moving back away from the crimping anvil on the return stroke of the shuttle member. Quinn discloses a typical feed mechanism with teeth that engage the slots on the carrier tape, but also discloses a guide plate which defines a pair of opposing clamping jaws for engaging and gripping outside surfaces of the tape for pulling the tape laterally off the path and away from the crimping die to break the terminal away from the tape.
U.S. Pat. No. 5,483,739 to Smith et al. and U.S. Pat. No. 5,517,749 to Zuin are each directed to an electrical terminal applicator with improved crimp height adjustment plate means. Smith et al. discloses an adjustment plate means which adjusts the crimp heights of the two crimping dies in an electrical terminal applicator wherein the adjustment plate means includes two adjusting plates which are continuously or gradually adjustable by employing ramped adjusting surfaces versus the finite number of positions of adjustment afforded by the calibrated plates of the prior art. Zuin describes a calibrated disk which can be retrofitted on existing applicator rams and includes a flexible adjusting plate mounted for rotation about an axis to selectively interpose projection means between the press ram and a first adjustable plate means to provide further adjustment of the shunt height of the crimping die.
U.S. Pat. No. 5,577,318 to Smith et al. describes an electrical terminal applicator with improved track adjustment means for a track which guides tapes with terminals secured thereto. An applicator ram is drivable in a first path through a working stroke towards, and a return stroke away from, a crimping anvil. A track guides the strip in a second path which intersects the first path of the ram and includes a track portion mounted for adjustable movement in a direction transverse to the second path. An adjusting screw is threaded into a transverse hole in the movable track portion for adjusting the position of the track portion in the direction transverse to the second path and a locking set screw is threaded into the transverse hole for jamming against an end of the adjusting screw to lock the adjusting screw and, thus, the track portion in any position of adjustment.
U.S. Pat. No. 6,026,562 to McMillin et al. discloses a global terminal assembly die of a modular design comprising a base unit assembly having several assemblies attached thereto. The possible removable assemblies include a slide retainer assembly, a terminal feed assembly, a terminal guide and brake assembly, an upper tool pack assembly, and a lower tool pack assembly. A mechanical feed assembly is disclosed which includes a feed finger that is attached to a trolley by a feed adjuster. The feed finger of the feeding mechanism cooperates with a guide and brake assembly to advance a terminal strip through the guide and brake assembly to a crimping area between the upper and lower tool pack assemblies.
Finally, U.S. Pat. No. 6,655,013 to Wilson et al. describes an applicator machine including a wire guide carried by the ram of the machine for guiding a wire into position for crimping a single-sided flag terminal thereto. The wire guide has a wire guiding surface that cooperates with lead-in angled surfaces of the crimping tool to guide the wire into alignment with the terminal.
Many companies which produce wire and cable assemblies are required to handle a wide variety of crimp terminals of varying sizes, shapes, etc. in order to satisfy customer demands. As a result, these companies must own or lease a large number of applicators in order to be able to produce a wide array of terminal products. The costs associated with owning or leasing these applicators is a major contributor to the overhead costs for the business.
Attempts have been made to reduce the cost to own or lease applicators. In one example, a product was offered that consisted of a base applicator body with interchangeable anvils, shear blocks, blades, guides, and other parts. It was intended that the end user of this type of applicator, such as personnel at wire and cable assembly companies, would purchase one (or a few) applicator bodies. Instead of ordering one complete applicator for each terminal type, only a set of parts (i.e., an anvil, shear block, blade, guide, and other items) would be needed for each terminal type and each set could be fitted onto the base applicator. Given the substantial reduction of complete applicators required, a substantial cost savings was expected. In practice, however, the cost savings was never fully realized.
Shortcomings of these prior art interchangeable applicators were based in part because little to no improvements were made to the terminal feed mechanism. Because the terminal feed mechanism remained an integral part of the mechanical workings of the applicator, no provisions existed to adapt a single feed mechanism to accommodate a wide variety of terminals. A large number of base applicators were therefore required to solve this problem, thereby defeating the goal of using one (or a few) base applicators and eroding any cost savings that was otherwise achievable.
Accordingly, there remains a need for terminal applicator apparatuses, systems, and methods for feeding, guiding and advancing a wide variety of terminals to enable terminal-specific parts (i.e., anvil, blade, and shear block) to be easily interchangeable.